Catching up on the last week in comet and asteroid discoveries… A week ago new NEA announcements were coming left and right but the flood completely stopped a few days before Full Moon. Most surveys take a break for a few days around Full Moon since the bright sky is really not conducive for finding much of anything.

Last week saw one and probably two comet discoveries. C/2010 S1 (LINEAR) is a large perihelion (q = 4.4 AU) long-period comet. Currently 17th magnitude and 8.5 AU from the Sun (almost the distance of Saturn), it should brighten to magnitude 12-13 near perihelion in the summer of 2013. This comet marks the 44th (non-SOHO-STEREO) comet discovery of the year and LINEAR’s 199th comet find.

2010 BK118 was first seen back in January by the WISE (Wide Infrared Space Explorer) spacecraft. WISE is conducting a survey of the sky at 4 infrared wavelengths. Though not specifically designed to find asteroids/comets, the spacecraft observes at wavelengths optimal for finding these types of objects. Though not identified as anything special back in January, it was independently rediscovered by LINEAR last week. After a few days of observation, January’s WISE object and this month’s LINEAR object were linked as one and the same. So far there have been no reports of cometary activity even though the orbit is very cometary (long-period type). If it is truly a extinct or dormant comet than it is very large for a comet nucleus at H = 10.2 and a diameter of ~60 km. I’d be very surprised if this object doesn’t turn out to be an actual comet when larger telescopes are pointed its way.

2010 SW3 passed within 0.0058 AU of Earth on Sept. 10. This distance equals 540,000 miles, 860,000 km or 2.1 Lunar Distances. The 10 to 30 meter in diameter rock was discovered by the Mount Lemmon Survey eight days after close approach.